Telephone signal device



Sept. 1; 1925.

F. H. N. WOYHLERS TELEPHONE SIGNAL'DEVICE Filed April 14. 1921 2Sheets-Sheet l INVEN TOR.

A TTORNEY.

sept. 1'; 1925. I 1,551,722

A E.' H. N. woHLERs TELEPHONE S IGNAL DEVICE Filed April `14. 1921 2Sheets-Shea?. 2

,www ,ad

Patented Sept. 1, 1925.

UNITED. STATES PATENT oF'FflcE.

FRIEDRICH H. N. WOHLEB/Sl OF JAMAICA, NEW YORK, ASSIGNOR TO DICTOGRAPHPRODUCTS CORPORATION, A CORPORATION OF VIRGINIA.

TELEPHONE SIGNAL DEVICE.

Application med April 14,1921. serial No. 461,282.

i nection with intercommunicating telephones.

In various telephone and similar systems, certain stations may berovided with a plurality of visual signed/devices, each corresponding toa different distant station, andwith a buzzeror audible signal deviceand circuit which may be controlled singly or in common by alll of thevisual signal devices, to be rendered active whenever any visual signaldevice is shifted to a full indicating position. This shifting of thedevice is usually accomplished by means of an electromagnet which isenergized by the closin of a circuit thereto from the correspondingdistant station. The circuit of the electromagnet is opened to permit ofthe return of the visual signal to its normal position whenever thecalling party discontinues the calling attempt or the called partyconnects his instruments with the calling party. It often happens thatthe party at the called station is absent at .the time the call is madeand upon his returnl desires toA know whether or not attemptstocommunicate with him have been made during his absence, and if so, theidentification of the calling station. It has been proposed to furnishsuch a notification of unanswered calls by locking the visualindicators, when operated during a call, in their call indicatingposition, but where audible signals are controlled thereby andconsiderable delay occurs in the return of the called party the audiblesignal batteries soon run down and have to be replaced. The continued operation of the audible signal is also often objectionable to othernearby parties.

An object of the invention is to provide a switchboard construction forintercommunicatin telephone systems which will visually an audlblyindicate all calls and identify the calling station, which will indicateto the called partythat an ineffectual attempt to commumcate with himhas been made by another station, and identify that station, which willaccomplish these. results with a minimum of deterioration of batteriesor consumption of energy, and in which the indicator will beautomatically restored to normal non-indicating position by the act ofcalling the prior calling station from the prior called station. Afurther object is to provide a construction of this kind and for thisVpurpose which is simple, eficient, reliable, inexpensive, and easilyinstalled on existing switchboards withA a minimumo changes in existingconstructions. Other objects and advantages will be apparent from" thefollowing descriptions, and the novel features of my invention will beparticularly pointed out in the claims. .l

In carrying my invention into practice I may provide a latch for eachvisual indicator for automatically preventing its complete return tonon-indicating position, at the cessation of an unanswered call from adistant station, but permitting a return sufficient to open the circuitof the audible signal device, and also indicate by its position that anunanswered call was received. The

latch is arranged to be operated to release the visual in dicator uponan operation of the switch during the completion or breaking of theconnections incident to the answering of the call, or duringa specialreleasing operation.

In the accompanying drawings:

Fig. l is a side elevation Yof a switch board uni constructed inaccordance with my inven ion with the visual indicator in one indicatingposition;

Fig. 2. is a front elevationpf the same;

Fig. 3 is a side elevation of the same withv some of the parts inpositions dii'erent from those of Fig. l;

Fig. 4 is a front elevation of the same; Fig. 5 is a side elevation ofthe samev with some of the parts in a still different position; y

Fig. 6 is a front elevation of the same; Fig. 7 is a side elevation ofthe same showing the positions of the parts, d'uring the receipt o acall;

.Fig. 8 is front elevation of the same, and

Fig. 9 is a wiring diagram.

In the illustrated embodiment, a frame unit l of a switchboard carries`upon its rear side an electromagnet or relay'2, and upon mounted apivoted armature 5,which is responsive to the influence of theelectromagnet. The armature carries a rigid arm 6, extending from oneside thereof and along one side of the electromagnet toward the faceplate 3. The frame 1 is provided on the l side abutting the face plateand opposite the window with a slot 7 into which the free end 8 of thearm is turned to form an indicating element. lVhenthe electromagnet isdeenergized the indicating arm normally lies at the bottom of theA slotand holds the armature away from the electromagnet as illustrated inFigs. 5 and 6. When the electromagnet is energized, the armature will beattracted and carry the indicating end 8 of arm 6 toward the top of theslot and behind the window as illustrated in Figs. 7 and 8,whichposition of the arm 6 represents the full indicating position andvisually notities the attendant'at that station that a certain stationis calling. If the call is unanswered, a discontinuance of the callcauses. a deenergization of the electromagnet 2 and the arm 6 falls. Abell crank pawl 9, pivoted tothe frame unit 1, is normally urged bygravity or a suitable -spring to rotation in a direction to bring one ofits arms 9a below the indicating arm 8. The arm 9n is normally held bythe arm 8 at one side thereof when arm 8 is .1n its lower non-indicatingposition. Upward movement ot the arm b during a call releases the pawlautomatically and permits 1t to move to bring the arm 9 beneath the arm8. Vhen the arm 8 falls it engages the end of the pawl and is held in anintermediate indicating position as illustrated in Figs. 1't0 4.

A switch key 10 is pivoted in the frame unit and extends through anaperture 11 in the' facev plate for manual operation. spring stripcontact 12 is normally in contact with a spring contact'l forcontrolling the circuit to the electromagnet but `is shiftable by one ofthe cam rollers 14 on an ex* tension of the key out of engagementtherewith and into engagement with a spring contact strip 15 controllingthe talking circuit whenever the key is moved upwardly.A The free end ofstrip 12 is offset tangentially of a cam roller so that when the key isshifted upwardly, the strip 12 will be locked in engagement with strip15 and will yieldingly Ahold the key in upper position as limited by alug 16 of the key which engages with the face plate. Spring strips 17extending over the cam rollers yieldingly limit downward movement of thekey beyond its normal or straight out position, while a second lug 18 onthe key by its engagement witlrthe face plate limits downward movementof the key. The strips 12 and 17 engage on opposite sides of the camrollers 14, when the key is vin normal straight out position andyieldthe action of gravity is ordinarily sufficient. A,

Limited downward movement of the key beyond normal position,l asillustrated in Figs. 5 and 6 will force the free end of one of thestrips 17 upwardly and through it carry the pawl to a position in whichit releases the indicating arm. An arm 18a on the armature is adapted tomove into engagement with a spring contact 19 carried by and insulatedfrom the electromagnet when the armature has shifted the indicator toapproximately its full indicating position. A battery 2O is connected bywire 2l to a buazer, or other suitable audible signal device 22. Thebuzzer is connected by a wire 23 with each of the contacts 19 carried bythe electromagnets or relays 2, so that each pair of contacts 18a and 19may complete the circuit through the bell independently of the' others.The contacts 19 are so disposed relative to arms 184 that when the armSgis held in an intermediate indicating position the contactsv 18 vand19. of the corresponding electromagnet will be in an open circuitcondition. The audible signal circuit is diagrammatically illustrated inFig. 9, in which only portions of the other circuits are shown, thecomplete circuits being illustrated and described in the U. S. PatentNo. 1,160,125.

In use let it be assumed that a call is received at the stationl Cthrough a wire 2/1 from a distant station A, the key 10 at station CYbeing in normal position. The calling circuit includes contact strips 12and 13 and. electromagnet 2 corresponding to station A. The energizationof this electromagnet 2 moves its indicator to full indicating positionand through contacts 18l1 and 19.closes the audible signal circuit toandibly call attention to the fact that another station is calling, theidentification of the calling station being given by the raisedindicating arm 8 corresponding to that station.

When a 'key 10 at station C correspondin to the visual signal theneffective is operated llO i upwardly from the Fig. 1 to the'iFig. 3position, the strip 12 will be separated from contact with strip 13 toopen the circuit through the energized electromagnet 2 permitting theindicator to fall, and connect the wire 24 instead to the talkingcircuit with the distant station. The visual signal arm 8 thereupondrops but is held in an intermediate position by the'pawl or lever 9which moved beneath the arm 8 when the latter was moved to its fullindicating position by the energized electromagnet. In this intermediateposition thd contacts 18a and 19 are separated and the buzzer circuit isopen.y During the return movement of the key to its normal straightoutposition at the conclusionof the conversation, the

' spring strip 12 usually imparts enough energy to the key to carry itagainst the upper strips 17 and shift pawl 9 to release the arm. The armthen drops to the bott-om of the slot 7 which is its normal position, asillustrated in Figs. 5 and 6. If the return of the keyfails to vreleasethe arm 8 from the pawl, the key `can be slightly depressed asillustrated in Figs. 5 and 6 to force the pawl clockwise and K releasethe arm 8. The spring strip 17 will then return the key to Anormalstraight out position when released.

It the call from station A is unanswered, the disconnection at station Aat thelabandonment of the call will open the circuit to the energizedyelectromagnet 2 and permit the indicator arm 8 to fall.- The pawl 9will prevent a complete return of the arm 8 but will allow it to returnfar enough to open the audible signal circuit, by separat? ing thecontacts 18a and 19` There will be no circuit iiowing through the systemand the intermediate position of the indicator arm8 will visuallyindicate that an unanswered call was received. The yoperation of thevkey 10 in calling station A to answer the call willcause a completerelease and return of the arm v8 as before. fThe pawl 9 )drops back atvone side of the arm 8 when the latter Ais released, so as to be readyto move beneath the arm when another call is received.

L :It will be obvious that various changes in the details and'arrangements herein described and illustrated for the purpose ofvexplaining the principle of -the invention, may be made within theprinciple and scope of the invention.

Lclaim: 1. A switchboard construction comprising an indicator movablebetween two indicatingpositions, remotely operable means for actuatingthe indicator from one position to the other, means adapt-ed toautomatically prevent complete return of the indicator to initialposition, but -permit return to an, intermediate indicating position, vaswitch device and means operative bythe switch device upon an operationthereof for releasing the indicator to permit of its complete return toits initial position.

'switch device, and means operable by the switch device as the latter isoperated for releasing the element to permit of its complete return.

3. A switch board construction comprising an electromagnet normallyincluded in a telephone circuit, an armature for the electromagnet andoperable thereby, a visual indicator operable by the armature betweentwo extreme indicating positions, an audible signal rendered active bythe visual indicator when the latter has been shifted to one of itsextreme positions by t e energization of the electromagnet, a device forpreventing complete return of the indicator upon deenergization of theelectromagnet but per. mitting return to an intermediate indicatingposition ',in which .the audible signal is inactive, a switch device fordisconnecting the electromagnet 'from the circuit and operable upon saiddevice to release the visual indicator and permit it to returncompletely to its Vother extreme indicating position.

4. A switchboard construction comprising an indicating member operablebetween two extreme indicating positions, means controlled from atelephone system for causing movement of the member from one of saidpositions to theother upon the receipt of a call from a stationcorresponding to said member, an audible signal device rendered otherposition, means operative upona movement of the member froml said oneposi tion to the other for preventing complete` return of the memberupon a cessation of the 'active by movement of the member to said y keyheld in normal position by said strips, a pivoted pawlv biased torotation in one direction against one of the strips to bring an armbeneath the indicating member for preventing a complete returnot thelatter to said one position but permitting a partial return, said pawlbeing operable to release -the member for complete return movement tosaid one position through the operation of the key to flex the strip.that is engaged by the pawl.

6. A switchboard construction comprising a frame unit, a face platehaving a Window therein carried bythe unit, means carried by the frameresponsive to an incoming call from a distant station for indicating theexistence of the call including a member movable -behind the window froma normal position to another position when a call is being received andtending to return to normal position when the call ceases, an audiblesignal device controlled by the member. and rendered active when thelatter is in said another position, switch mechanism for controlling acircuit to said distant Station, a pawlpivoted to the frame and biasscdto rotate to bring an arm thereof beneath the member when it moves fromnormal position to the other position and limit its return movement toan intermediate position in Which the audible device is inactive Whenthe call ceases, and switch mechanism controlling a circuit to saiddistant station operable to shift the pawl to release the member forcomplete return to normal position.

In witness whereof, I hereunto subscribe my signature.

FRIEDRICH H. N. VOHLERS.

